Communicable disease: an infectious disease transmissible (as from person to person) by direct contact with an affected individual or the individual's discharges or by indirect means (as by a vector)(Communicable Disease).
Communicable diseases, also known as infectious diseases, are caused by micro and macro organisms that invade the body causing illness. These organisms are: viruses, viroids, prions, bacteria, fungi, amoebas, protista
Communicable disease. (n.d.). Retrieved November 20, 2014, from http://www.merriam-webster.com/medical/communicable disease